Alterations in Surface Electromyography of the Upper Leg Muscles at Specified Respiratory Exchange Ratio Thresholds Ranges During a Maximal Exercise Test

Abstract

Introduction: Assessing muscle electromyography (EMG) in conjunction with physiological alterations to exercise may be valuable to determine a more holistic approach to exercise-induced fatigue. Methods: Thirteen, recreationally trained individuals (n = 7 female, n = 6 males) underwent a maximal exercise test. Throughout the test, physiological variables were measured in addition to surface electromyography (sEMG) of the upper legs. Physiological and sEMG data was then grouped in to four category thresholds based on respiratory exchange ratios (RER) greater than 0.95. Results: There was a main effect of group (p < 0.001) as an increase in exercise intensity assessed by RER threshold ranges resulted in a subsequent reductions in sEMG frequencies with the exception of the sEMG frequencies recorded at VO2peak (p < 0.055). Conclusions: Upper leg sEMG frequencies decrease with increases in high intensity exercise, with the exception of near maximal loads.